Temperature insensitive multi-channel light amplification systems on SOI platform

We present a theoretical analysis of a novel multi-channel light amplification photonic system on chip, where the nonlinear Raman amplification phenomenon in the silicon(Si) wire waveguide is considered. Particularly, a compact and temperature insensitive Mach±Zehnder interferometer filter working as demultiplexer is also exploited, allowing for the whole Si photonic system to be free from thermal interference. The propagation of the multi-channel pump and Stokes lights is described by a rigorou...     

Electron–phonon coupling in topological insulator Bi_2Se_3 thin films with different substrates

Broadband transient reflectivity traces were measured for Bi_2 Se_3 thin films with various substrates via a 400 nm pump–white-light-probe setup. We have verified the existence of a second Dirac surface state in Bi_2 Se_3 and qualitatively located it by properly analyzing the traces acquired at different probe wavelengths. Referring to the band structure of Bi_2 Se_3, the relaxation mechanisms for photo-excited electrons with different energies are also revealed and studied. Our results show a second rise of the transient reflection signal at the time scale of several picoseconds. The types of substrate can also significantly affect the dynamics of the rising signal. This phenomenon is attributed to the effect of lattice heating and coherent phonon processes. The mechanism study in this work will benefit the fabrication of high-performance photonic devices based on topological insulators.     

面向不确定性影响源的社会网络影响力传播抑制方法

社会网络中影响力传播的有效抑制是社会网络影响力传播机制研究所关注的问题之一。该文针对未知影响传播源,或传播源信息具有不确定性的情况,提出面向不确定性影响源的影响力传播抑制问题。首先,为有效提高抑制算法的执行效率,讨论竞争线性阈值传播模型下影响源传播能力的近似估计方法,进而提出有限影响源情况下,期望抑制效果最大化的抑制种子集挖掘算法。其次,对于大尺寸不确定性影响源的情况,考虑算法运行效率和抑制效果之间的有效折中,提出基于抽样平均近似的期望抑制效果最大化的抑制种子集挖掘算法。最后,在真实的社会网络数据集上,通过实验测试验证了所提出方法的有效性。     

掺稀土光纤的光子暗化研究进展

掺稀土光纤是光纤激光器的基础,而掺杂光纤的光子暗化是影响激光输出功率稳定性的重要因素。综述了光子暗化的产生机理、光子暗化对光纤激光器的影响及其抑制方法,旨在为相关研究提供参考。